Endurance improved by ingestion of a glucose polymer supplement

The effect of glucose polymer (GP) ingestion upon endurance performance during walking exercise at 45% VO2max was examined. Also, performance on a battery of psychomotor tests was assessed to determine if exhaustion from endurance exercise was related to central nervous system dysfunction. Ten trained male subjects ingested approximately 120 g of GP in four equally-divided dosages 60, 90, 120, and 150 min following the start of exercise. This treatment significantly increased time to exhaustion by 11.5% as compared to the control (C) group (GP=299.0 +/- 9.8 min; C=268.3 +/- 11.8 min). No difference in VO2 (1 X min-1) or perceived exertion was noted between treatments. As a result of the GP feedings the rate of carbohydrate utilization during the GP trial was 0.53 g X min-1 greater than during the C trial. However, during the GP trial plasma glucose did not fall below the pre-exercise level and was significantly higher than the C plasma glucose concentration at exhaustion. No differences in psychomotor performance between treatments or between rested and exhausted states for either the C or GP treatments were noted. These data suggest that exhaustion was not a result of hypoglycemia or central nervous system dysfunction and that glucose polymer supplements may enhance endurance capacity.